SDLS213B − DECEMBER 1983 − REVISED NOVEMBER 2004
SN54221, SN54LS221, SN74221, SN74LS221
DUAL MONOSTABLE MULTIVIBRATORS
WITH SCHMITT TRIGGER INPUTS
PARAMETER MEASUREMENT INFORMATION
tw
3V
B†
0V
≥
60 ns
3V
CLR
0V
tPLH
Q
VOL
tPHL
Q
VOL
CONDITION 1: TRIGGER FROM B, THEN CLR
tPLH
VOH
tPHL
VOH
3V
B†
0V
≥
60 ns
3V
CLR
0V
VOH
Q
VOL
CONDITION 2: TRIGGER FROM B, THEN CLR
3V
B†
0V
≥
50 ns
CLR
0V
Triggered
Q
Not Triggered
CONDITION 3: CLR OVERRIDING B, THEN TRIGGER FROM B
† A is low.
VOL
tw
VOH
≥
0
tsu
3V
Figure 1. Switching Characteristics
10
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•
DALLAS, TEXAS 75265